Sighting-telescope for indicating ships&#39; oscillations.



H. G. MUSTINL SIGHTING TELESCOPE FOR INDIOATING SHIPS ()SOILLATION. APPLICATION FILED J I'ULY I 1905. RENEWED NQV. 15, 1907. 992,933, Patented May 25, 19

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APPLICATION FILED JULY 1, 1906. REHBWED'NOV. 15, 1907.

Patented May 25, 1909.

2 SHEET8-BEEET 2.

SIGHTING TELESCOPE FOR INDIGATING SHIP'S OSOILLATION. 922,938.

1.0 lowing to be a full, clear, and exact descri tion of the invention, such as will enab e i of the primary object.

UNITED sTA'rns PATENT OFFICE.

HENRY (3. MUSTIN, OF THE UNITED STATES NAVY.

srom'nte-rnnnscorn roa INDICATIN'G smrs oscILLA'rIons.

no.'s22,9ss.

Specification of Letters Patent.

Patented-May 25, 1909.

7 Application filed July 1,1905, Serial No. 267,984. Renewed November 16, 1907. Serial No. 402,328.

in the county of Philadelphia and State of Pennsylvania, and at resent stationed at- 'VVashington, District 0 Columbia, have invented certain new and useful Improvements in Sighting-Telescopes for Indicating Ships Oscillations, and'Ido hereby declare the lolothers skilled in the art to which it apper talns to make and use the same.

a This invention relates to an improved con- I struction of telescopes adapted to receive and project rays, from a point outsideof the.

nonnal field of" view, within the telescope tube in such manner that the image of the secondary object is positioned on the image The invention further resides in the application of an instrument of this character as- 'lation of the ship will be indicated on the image of the rimary object or target'formed within the te esco e tube so thatthe gunpointer can clear y determine the approach 1 of the end and the end of the ships oscilla-' image tion, and thus regulate'the time of firing;

It is well known that in naval gunnery the image of the target, sea andsky, seen in the tion due to rolling'or pitching of theship on which the telescope is situated. Now, so long as the. elevating gear of the gun is stopped, the gun-pointer, at the telesco e, is informed of the direction and'speed 0 this apparent motion by means of the cross wires w ich-are in the same plane in the telescope as the image of-the target. Apparentl this the orizontal cross wire at a s eed which is governed by the angle of re] or angle of pitching, or both combined. Toward the end ofarolling or pitching oscillation of the ship, the apparent vertical speed-of-the targetslows down and at the end-of an oscillation the gun and consefluently the telescope, is

y witnot moved vert'ica referenceto the alternately rises above and falls 'elow ship, and this isthe only indication of verti-' cal apparent motion of the target.

It is generall desirable to fire at the end of the ships oscil ation in order to avoid vertiwires must be kept in the vicinityof the tar-.

get image and to do this requires-motion of the elevating gear of the gun. as the elevating gear of the gun is moved, the telescope moves with it vertically, and-conse- But assoon quently the horizontalcross wire (reference I for apparent vertical motion of the target) takes up a vertical motion. The gunpointer then has to get his idea of the approach of the end andthe end of the ship's tion of the image of the target with the actual motion of the cross wires. Since neither of these motionsis at a constant speed it is very diflicult for the gun-pointer to note'the oscillation by comparing the apparent moapproach of thecnd of the ships oscillation, an

consequently he is likely to miss-the opportunity of bringin cross wires intersection on the target at t \e instant the ships oscillation stops.

The object of this invention isto project on or near the'image of the target anindicat'or which will inform the gun-pointer of'the approach of the end and t'he end'of the ships oscillation. This may be accomplished by the use of an auxiliary objective adapted'to receive the rays from an ob'ect or indicator ada ted to'be fixed vertically with relation to -t eship, and preferably locatedon the inside wall of the turret or on any other suit-"- able support movable with the gun platfo'rnrwhen a turret is not used, theprojected rays from the second'object-iv'e being suitably deflected to the eye piece by a combination of prisms or other re '"ecting' surfaces hereinafter referred to.

To more fully describe the invention and the particular features of novelty embodied in the claims, reference is had to the accompanying drawin s illustrating an application ofthe same, in w iich like reference characters designate the same parts in the several views, and in which, I

Figure 1 is a diagrammatic view-illustrating sin-application of the invention. Fig. 2

is-a-front' view ofthe preferred type of indicat'or. Fig. 3 is a side'cl'evation of same, and

Fig. 4 is a longitudinal transverse section through an angular sight telescope with my present invention applied thereto, the arrangement of prisms being shown in )lan.

1 designates a ship's turret or simi ar protective guard.

2 designates the objective, 3 the first erecting lens, 4 the second erecting lens, 5 the field lens, 6 the cross wires, and 7 the eye lens of an ordinary telescope. Between the objective 2 and the erecting lenses-are a pair of adjacently disposed prisms 8 and 9 having parallel faces, the two prisms forming substantially a para-llelogranunatie figure.

10 is a'totally reflecting prism disposed adjacent said combined prisms and adapted to receive the rays from the auxiliary objective 11 which latter may be mounted in an adjustable tube member to properly bring the secondary object or indicator in focus on the real image.

12 designates the secondary object or indicator before referred to. This indicator 12, as shown in Figs. 2 and 3, is preferably in the nature of a box having a front face 12 of an opaque material curved to form an arc with the pivotal axis of the telescope, and provided with a plurality of slanting slots 12 arranged in rows and closed by any suitably colored translucent material. Within the box is arranged an electric bulb or bulbs 12 or any other li hting medium.

Letting X esignate the optical axis of the main telescope prior to the entr of the rays into the prisms 3 and 9, and .r the same axis after the emergence of the rays from said prisms, and letting Y designate the optical axis of the secondary objective, then the rays of light entering the main objective 2 pass through the prism S to the point 0 and striking the lower face of that prism at an angle greater (or at an angle with the normal less) than the critical angle of glass, there is only a partial reflection of the rays along the line 3 the body of the rays being refracted at the point into the prism 9 where they are again refracted, emerging from this latter prism substantially in alinement to their direction of entry into the first prism. The rays from the indicator 12 are projected in the. direct-ion of the axis -Y and entering the prism 9 at right angles to its side surface, strikes the upper surface of said prism at the point 0, the angle of incidence eing less than thecritical angle of glass and there 'is therefore a partial reflection of the rays in the direction of 1 the greater portion of the rays being diverted by refraction and passing through the prism 8 substantially as indicated at '3 It will thus be seen that the secondary object or indicator 12 will not be so intensified on the real image formed at 6, owing to the loss of the greater portion of the rays, and it is for this purpose particularly that I use the special form of indicator, as

from experiment it has been found that an illuminated suitably colored object will show -in is illustrated a telescope as before mentioned having an angular line of sight, and preferably of the construction shown in my I. S. Patent, No. 778,694 of December 27, 1904, the prism 10 is done away with, the secondary objective 11 in this construction, as well as the main objective opening 2, is disposed transversely of the main optical axis, and the erecting lenses are also dispensed with, being replaced by the combination of prisms 3 and 4 2 in this construction being a total reflecting prism projecting the rays from the ob'ective openlng to the objective lens 2. T e cross wires 6 in this construction as described in my patent above referred to are preferably mounted in an adj ustable sleeve 6 located within the eye tube 6" and operated by a rack and pinion construction 6 6 designates an eye piece with the usual magnifying lenses. The assage of the rays in this construction wi -bc apgi arent from the description with reference to 1g. 1.

In operation the effect of the use of the indicator 12 and its projection within the telesco e, as heretofore explained, is the same as if t e indicator was an object, theoretically speaking, projected on the target and moving thereon in a degree corresponding with the oscillation of the ship containing the instrument, hence as the ship approximates the end of its oscillation, the moving object slows down also so that the 'unointer at the telescope will be ositive ly a vised of the approach of-the en and the end of the oscillation and the elevating gear can be operated accordingly.

As before mentioned, any suitable indicator may be used, the construction in Figs. 2 and 3 being preferable for the reason stated and the particular disposition of the slots 12 thereon are placed diagonally so that they will not be confused with the cross wires.

It will be understood that I do not limit myself to the exact details as shown herein, the same, for the purpose of illustration only, designating a preferred embodiment of the invention.

What I claim is:

1. In a sighting telescope, the combina tion with a main objective, erecting means and eye lens, of means for projecting, into the telescope, a secondary object located out of the normal field of the telescope, comprising a reflector located within the telescope tube and so disposed with relation to the objective as to permit of the passage of the rays therefrom through said reflector, and auxiliary means for projecting the rays from said sec- 3 of glass for projecting an image of said indiondary object to said reflector at an angle of Z cator within the telescope to indicate the v i oscillation of the ship. 2. In asighting telescope, the combinai incidence less than the critical angle of glass.

tion with a main objective, erecting means, and eyelens, of means for pro ecting, into the telescope, a secondary object located out of the normal field ofthe telescope, comprising a reflector located within the telescope tube between the objective and erecting means and so disposed with relation to the objective as to permit of the passage of the rays therefrom through said reflector, andauxiliary means for projecting the rays from said secondary object tosaid reflector at an angle of incidence less than the critical angle of glass.

3. In a sighting telescope, the combination with a mainobjective, erecting means and eye lens, of means for projecting, into the telescope, a secondary object located out of the normal field of the telescope, comprising an auxiliary objective and a pair of prisms each having one of their faces disposed substantially at right angles to the optical axis of-the main and auxiliary objectives, respectively, and opposed parallel faces disposed at angles, to said optical axes,

greater than the critical angle of glass.

4. In a sighting telescope for marine gunnery, the combination with a sighting tele- I scope, of reflecting means associated therewith for indicating, in connection with the objects ,viewed the oscillation of the ship.

5. In a sighting telescope for marine gunnery, the combination with a sighting telescope, of reflecting means associated there- -witi for indicating, within the telescope tube, and in connection with the objects viewed, the oscillation of the ship.

6. In a sighting telescope for marine gunnery, the combination with a sighting telescope, of means associated therewith for indicating the oscillation of the ship, ,cOlIlPllsing a vertically fixed indicator carried by the ship, and means for projecting the image of said fixed indicator into the telescope.

7. In a sighting telescope for marine gunnery, the combination with a sighting telescope, of a vertically fixed indicator carried by the ship, a reflector located within the telescope tube and so disposed with relation to the objective as to permit of the passage of the rays therefrom through said reflector, and auxiliary means for projecting the rays from said indicator to said reflector, at an angle of incidence less than the critical angle 8. In a sighting telescope for marine gunnery, the combination with a sighting telescope provided with a main ob ective, erecting means and eye lens, of a vertically fixed indicator within'the telescope tube to indicate the oscillation of the ship.

9. In a sighting telescope for marine gunnery, the combination with a sighting telescope, of an indicator carried by the ship in a vertically fixed position and comprising an illuminated object, and means for projecting the image of said fixed indicator into the telescope tube-for indicating the oscillation of the ship.

10. In a sighting telescope for marine gun- 'nery, the combination with a sighting telescope, of an indicator separate from said telescope and having a face of opaque material provided with a plurality of slots therein and illuminating means therefor, and means for projecting the image of said indicator into the telescope tube for indicating the os eillation of the ship.

1]. In a sighting telescope for marine gun- ;nery, the combination with a sighting telescope, of an indicator carried by the ship having a face of opaque material, provided with a plurality of slots and illuminating means therefor, and means for projecting the image of said indicator into the telescope for indicating the oscillation of the ship.

12. In a sighting telescope for marine gunnery, the combinati n with a sighting tele scope, of an indicator carried bythe ship having an opaque curved face provided with a plurality of diagonal slots and means for illuminating same, and means for projecting an image of said indicator into the telescope tube for indicating the oscillation of the ship.

In testimony whereof, I aflix my signatu re in presence of two witnesses.

HENRY C. MUSTIN.

Witnesses MARY B. SIMPSON,

ELLA M. BRANDT. 

